Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Bubble columns


Fluid Dynamic in Bubble Columns with Heat Exchanger Internals

Burhan Sadeq Abdulrazzaq

Engineering and Technology Journal, 2014, Volume 32, Issue 11, Pages 2815-2829

The effects of vertical cooling internals on the gas hydrodynamics was studied in gas-liquid system (bubble columns) for column diameters, 15 and 30 cm in the absence and presence of internals (the % occluded area by internals 5, 10, and 20%). The superficial gas velocity was varied in the range 0.8-30 and 0.8-7.6 cm/s for 15 and 30 cm column diameters respectively. The effect of internals on the bubble dynamics in columns was assessed using the electroresistivity probe technique. The overall gas holdup is measured experimentally by bed expansion technique. The experimental results show that the increased in percentage coverage of cross sectional area by internals causes an increase in the overall gas holdup values, gas holdup radial profiles, bubble rise velocity, bubble frequency and reduce average bubble diameters. Correlations have been used for the estimation of the gas holdup in gas-liquid system bubble column. The overall gas holdup can be easily predicted from .Comparison of the model predictions with the experimental data shows agreement with error 0.017 which ensure the reliability and confidentiality of the adopted the correlations to be used in further designation and scale-up purposes.

A Hydrodynamic Study in a Sieve Plate Sectionalized Bubble Column

Burhan Sadeq Abdulrazzaq

Engineering and Technology Journal, 2011, Volume 29, Issue 6, Pages 1145-1156

The sectionalization of conventional bubble columns to tray bubble column by
perforated trays has been used in chemical, biochemical, and petroleum processes
as an effective way to improve the gas-liquid contacting efficiency, and reduce
liquid backmixing. In this study, an experimental semi-batch tray bubble column
setup has been built. Column 0.15 m inside diameter and total height of 2.20 m is
sectionalized into four stages using three perforated plates to investigate the
effect of tray geometry, superficial gas velocities and liquid phase physical
properties on overall gas holdup. The overall gas holdup is measured
experimentally by bed expansion technique. For studying the effect of physical
properties of the liquid phase, two different gas and liquid systems are used (airwater
and air-methanol solution).Methanol solution was used as the liquid phase
to simulate the hydrodynamic behavior of the high gas holdup systems.
Remarkable increases of up to 80% in the overall gas holdup have been observed
in tray column as compared to conventional bubble column when this liquid
system was used. Experimental results of tray bubble column shows significant
increase the overall gas holdup in comparison with conventional bubble column.
Correlations have been used for the estimation of the fractional gas holdup in
bubble column with and without tray. Comparison of the model predictions with
the experimental data and with the published data of other authors shows fine
agreement which ensure the reliability and confidentiality of the adopted the
correlations to be used in further designation.

Studies Pressure Drop of gas-Non-Newtonian Liquid Two Phase Flow in Bubble Column

Ali H. Jawad

Engineering and Technology Journal, 2009, Volume 27, Issue 7, Pages 1336-1350

An exclusive study has been done on experimental investigation of the two-phase flow
pressure drop in an air-non-Newtonian liquid (CMC solutions) system in bubble column.
The effects of gas and liquid flow rate on two-phase pressure drop have been illustrated.
Experiments in a 0.2-m diameter, 2.4-m-high bubble column were carried out to determine
the pressure drop. At the selected superficial velocities, two flow regimes were observed:
heterogeneous bubbling flow and heterogeneous churn turbulent flow, they were identified
through the slope changes in the plots of pressure drop and gas holdup. The pressure drop
did not seem to be affected by the superficial liquid velocity and it was increased as the
superficial gas velocity decreased or the CMC concentrations increased.